The Volume Behavior of Autogenous Iliac Bone Grafts After Sinus Floor Elevation: A Clinical Pilot Study
Iliac crest is still regarded as one of the most viable source of autogenous graft materials for extensive sinus floor elevation. Three-dimensional resorption behavior has to be taken into account in anticipation of the subsequent insertion of dental implants. We performed 3-dimensional volume measurements of the inserted bone transplants in 11 patients (6 women and 5 men; mean age = 2.3 years) who underwent bilateral sinus floor elevation with autogenous iliac crest grafts. In order to determine the respective bone graft volumes, cone-beam computerized tomography studies of the maxillary sinuses were carried out directly after the operation (T0), as well as 3 months (T1) and 6 months (T2) postoperatively. The acquired DICOM (Digital Imaging and Communications in Medicine) data sets were evaluated using suitable analysis software. We evaluated statistical significance of graft volumes changes using a linear mixed model with the grouping factors for time, age, side, and sex with a significance level of P = .05. 38.9% of the initial bone graft volume, which amounted to 4.2 cm3, was resorbed until T1. At T2, the average volume again decreased significantly by 18.9 % to finally reach 1.8 cm3. The results show neither age nor side dependency and apply equally to both sexes. Without functional load, iliac bone grafts feature low-volume stability in sinus-augmentation surgery. Further clinical and animal studies should be done to detect the optimal timing for implant placement.

Condensed and distributed graft material on the maxillary sinus floor.

Gray-scale–based interpolation of 8 layers in iPlan CMF 3.0 (BrainLAB, Feldkirchen, Germany).

A 3-dimensional picture of the segmented bone graft and its volume appear in the plan content.

Figure 4. Bone volume in cm3 (y-axis) at the time of T0, T1, and T2 (x-axis): a significant resorption of 57.8% between T0 and T2 can be seen. Figure 5. Pearson's correlation of age and bone loss between T0 and T2: no age-specific dependency can be observed. Figure 6. Effect of gender on bone graft's resorption: no significant effect on the resorption process can be seen.

Bone graft at the time of T1: the transplant presents itself fully osseously integrated.
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